I have written an app to retrieve data from a PWS on Weather Underground.
I will see if Athom will publish it, so if you have any interest in this then let me know so I can see if it worth pursuing for anything but my own use.

One thing that has come to light is that WU provide two keys. One is the short key that appears in thier control panel next in the device table. The other, and this is the one you need, is the long API key. That is shown on a separate tab. See the image below taken from my WU members page:

Added a UV senor to displayed items, but obviously this will only get a value if you station sends UV data.

Added a new ‘device’ that can be installed that shows information from the weather forecast for tomorrow. Enter the weather station ID and API key in exactly the same way as for the PWS device. The weather forecast data is updated every hour so the combined PWS and forecast request stay under the allowed 1500 request per day.

Let me know if there any issues. I will leave it in test for a few days and wait for feedback and if it is OK I will request that it is published next week.

It was also mentioned that LUX and Watt sensors are missing but as far as I can see that information is not provided by WU so I can’t do those. I must admit I am surprised that LUX is not available. If anyone sees it in the documentation then let me know and I will do my best.

If anyone wants to translate any of the text in the app that is in English then please let me know the English and translated text (plus language just in case I don’t recognise it). Or you can do it via a pull request on Github if that is easier for you. I would be grateful as, I guess, would other users.

@Adrian_Rockall i got the test version, removed and added it again. it nows also shows UV. although every value is still empty after 24 hours. wgen configuring in homey wu app app, it says ip assigned by your router, but the field name is called hub ID, a bit confusing. I gues you ment weather station ip here?
And what happens is you add wrong ip? any log if enabled?
Regards Ray, finaly my ws is in homey. So i can set greenhouse lightning on and off if thats is a condition in the flow would be awesome !!

A new version is available for test (0.0.1).
Changed the Forecast Wind Strength capability to Gust Strength.
Also a bit of optimisation and hopefully error message should be displayed
Thanks to everyone for the help with translations.

A new version is available for test (0.0.2).
Added Solar Radiation to the Station device.
Added triggers for all (hopefully) custom capabilities.
Clear error message when new data fetched.
Dutch translations for new stuff has been added with the help of Google plus the previous translations so I hope they are OK.